I'm quite forgetful so i know sooner or later im going to forget one or both of these. How would i go about changing a username or password? Also is there a forgotten password function?

There are several ways for you to change your username or password. If you have a My Profile atom set up on your website you can use that to change your details including your username and password. However if you do not have a My Profile atom you can go into the back end of your XPOR and select My Account from the menu. This will show you all your details which you can change. There is a Forgotten Password atom which you can setup and use in case you forget your password.